body dysmorphic disorder

noun

variants also body dysmorphia

: pathological preoccupation with an imagined or slight physical defect of one's body to the point of causing significant stress or behavioral impairment in several areas (as work and personal relationships)

People suffering from body dysmorphic disorder perceive themselves as ugly, fixating on a slight abnormality or an imagined flaw.

—Charles Q. Choi, Scientific American